• Food Science and Preservation
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• v.24 no.7
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• pp.1043-1051
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• 2017

Wild yeasts were isolated from domestic non-sterilized Makgeolli and their fermentation characteristics were analyzed to select the best fermentation seed culture. A total of 65 yeast strains isolated yeasts from non-sterilized Makgeolli and Nuruk. In order to select fermentable strains, hydrogen sulfide, $CO_2$ production ability, alcohol tolerance and aroma component production ability were analyzed. To screen the aromatic strains of isolates, media containing cerulenin, 5,5,5-trifluor-DL-leucine (TFL) and API ZYM kit were used. There were 36 strains resistance to cerulenin and all strains produced esterase and demonstrated tolerance against TFL. Hydrogen sulfide, which could degrade the quality of the fermented beverage, was not produced in 34 yeast. The correlation between alcohol tolerance of yeast and carbon dioxide production was analyzed by principal component analysis. YM22, YM31, YM32 and YM37 produced a total of 0.14-0.18 g/72 h of $CO_2$ indicating high fermentability. Alcohol tolerance was measured by alcohol concentration. YM32, YM37 yeast had 20% alcohol tolerance. As a result, alcohol and flavor characteristics of wild yeast isolated from non-sterilized Makgeolli were analyzed and it was confirmed that yeast was suitable for the production of alcohol.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1619-1627
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• 1999

Microbiological characteristics of gamma irradiated low salt squid Jeot-gal were examined. Following the fermentation periods, total bacterial cell, Lactobacillus spp., Staphylococcus spp., Streptococcus spp., Pseudomonas spp. and yeast cell number were counted on their selective media and some acid forming bacteria and Pseudomonas spp. were identified. As the gamma irradiation dose increased, the microbial density of early fermentation phase was reduced and the growth rate was delayed. The repression effects on microbiological growth by gamma irradiation were to be higher as salt concentration increased. Adequate conditions of salt concentration and gamma irradiation for low-salt squid Jeot-gal preparation were 10% and 10 kGy, respectively. Lactobacillus sp. 2, Micrococcus varians and Streptococcus sp. I were isolated from 5% salt containing squid Jeot-gal, and Micrococcus morrhuae was from 20% only while Lactobacillus plantarum and Lactobacillus brevis were widespread. Lactobacillus brevis, Pediococcus halophilus and Pseudomonas diminuta were sensitive and Lactobacillus plantarum, Micrococcus morrhuae and Pseudomonas sp. 3 were resistant to gamma irradiation. The diversity of microflora decreased as salt concentration decreased and gamma irradiation dose increased.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.122-126
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• 1996

Growth patterns of Saccharomyces cerevisiae NS 2031 and its total RNA contents were observed by a fed-batch fermentation with different media-feeding methods. With an exponential feeding pattern, both final cell concentrations and intracellular RNA contents decreased with increasing feeding rates. Intracellular RNA contents also decreased with the growth time. At the same feeding rate of the exponential pattern, final cell concentrations decreased with the increase of total sugar concentration whereas intracellular RNA contents increased. The highest cellular yield was 0.47 at the total sugar concentration of 10%. With increasing feeding rates of the parabolic feeding pattern, final cell concentrations decreased whereas intracellular RNA contents increased, showing a different tendency from the exponential feeding pattern. In comparison of two feeding methods, the exponential feeding pattern was better than the parabolic feeding pattern in terms of cell growth, cellular yields and intracellular RNA contents of Saccharomyces cerevisiae NS 2031. Also, the intracellular RNA contents of the exponential feeding pattern was found to be about 2% higher than that of the parabolic feeding pattern at the same instantaneous growth rate $({\mu}_{inst})$.

• Animal Bioscience
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• v.35 no.2
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• pp.281-289
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• 2022

Objective: The aim of this study was to characterize the exopolysaccharides (EPS)-producing lactic acid bacteria from Taiwanese ropy fermented milk (TRFM) for developing a clean label low-fat fermented milk. Methods: Potential isolates from TRFM were selected based on the Gram staining test and observation of turbid suspension in the culture broth. Random amplified polymorphic DNA-polymerase chain reaction, 16S rRNA gene sequencing, and API CHL 50 test were used for strain identification. After evaluation of EPS concentration, target strains were introduced to low-fat milk fermentation for 24 h. Fermentation characters were checked: pH value, acidity, viable count, syneresis, and viscosity. Sensory evaluation of fermented products was carried out by 30 volunteers, while the storage test was performed for 21 days at 4℃. Results: Two EPS-producing strains (APL15 and APL16) were isolated from TRFM and identified as Lactococcus (Lc.) lactis subsp. cremoris. Their EPS concentrations in glucose and lactose media were higher than other published strains of Lc. lactis subsp. cremoris. Low-fat fermented milk separately prepared with APL15 and APL16 reached pH 4.3 and acidity 0.8% with a viable count of 9 log colony-forming units/mL. The physical properties of both products were superior to the control yogurt, showing significant improvements in syneresis and viscosity (p<0.05). Our low-fat products had appropriate sensory scores in appearance and texture according to sensory evaluation. Although decreasing viable cells of strains during the 21-day storage test, low-fat fermented milk made by APL15 exhibited stable physicochemical properties, including pH value, acidity, syneresis and sufficient viable cells throughout the storage period. Conclusion: This study demonstrated that Lc. lactis subsp. cremoris APL15 isolated from TRFM had good fermentation abilities to produce low-fat fermented milk. These data indicate that EPS-producing lactic acid bacteria have great potential to act as natural food stabilizers for low-fat fermented milk.

• Journal of Mushroom
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• v.5 no.1
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• pp.43-49
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• 2007

Application of sludge wastes into the field may help soil fertility with physical, chemical and biological properties. Efficient use of sludge waste, however, requires an individual assessment of the waste products. A lot of experiment into the organic waste-treated soils has been done for decade. However, studies have not been carried out on the assessment of agricultural soil by Basidiomycota. This study was assessed the influence of sludge application on soil healthy in agricultural upland soils. The organic wastes selected for long-term application experiment in this study were municipal sewage sludge (MSS), industrial sewage sludge (ISS), leather processing sludge (LS), alcohol fermentation processing sludge (FS), and pig manure compost (PMC). To develop the soil healthy assesment method, soil samples were diluted by 20X with distilled water. After shaking at 200rpm for 30 minutes, the shaked sample was mixed on PDA(Potato Dextrose Agar). And sterilized at $121^{\circ}C$ for 20 minutes. Coriolus hirsutus (MKACC 50560) was inoculated on petri-dish including PDA mixed sample. After the media was incubated at $25^{\circ}C$ for five days, the mycelial growth of C. hirsutus was measured. When the mycelial growth on sample media was compared with growth on media contained PDA only, well grown media contained sample soil was assesed as healthy soil. The results suggest that the simple method by Coriolus hirsutus is a handy way to assess the healthy of waste sludge-applied upland soils.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.188-192
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• 1999

In order to minimize the mycelial pellet formation, one of the critical obstacles during the fermentation processes of filamentous fungi, an investigation was focused on the culture conditions(media and initial inoculum) and additives(soils, surfactants and polyethylene glycol 200) when a high phosphate-dissolving fungus, Penicillium sp. GL-101, was cultured in liquid media. Culturing the strain in PDB, SDB and YPD media, their pellet sizes decreased to the order of YPD > SDB > PDB. And at the high concentrations of the initial inoculum in the range from $1{\times}10^3\;to\;1{\times}10^6$ conidia/ml, the small sizes of pellet were formed in the PDB media. For the initial inoculum between $1{\times}10^7\;and\;1{\times}10^8$ conidia/ml, however, an amorphous pellet or loose aggregate was formed. The addition of soils, zeolite and diatomite, up to 1.0% decreased the pellet sizes to 3/4 and 1/2, respectively, but the pellet was increased to 2.5 times by the addition of bentonite. Surfactants also affected on the size of pellet; the addition of Triton X-100 and Tween 80 up to 1.0% decreased the pellet sizes maximally to 1/10 and 1/4, respectively, while SDS completely inhibited the fungal growth. Among the four additives tsted, polyethylene glycol 200 was the most effectively reduced the pellet sizes to $0.2{\pm}0.1$mm that resulted in about 25- fold reduction compared to the control.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.422-427
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• 2006

The culture media from Fomitopsis pinicola were extracted by methanol and examined growth inhibition against Helicobacter pylori. The culture media from 8 days fermentation of F. pinicola showed maximum inhibition activity on H. pylori in 0.25 mg as MIC value. The highest activity against H. pylori by MHCS agar diffusion medium by Fp-P1 in 22.7 mm ID among 3 peaks from methanol fraction of 8 days culture media of Fomitopsis pinicola which purified by ion-exchange chromatography. The Fp-P1 from DEAE-Sephadex A-25 have been analysed by TLC as Fp-T1, Fp-T2 and Fp-T3 by ninhydrin staining. Fp-T3 (Rf value : 0.67) was higher activity against H. pylori in 14.4 mm ID. Fp-T3 was identified as single band by HPLC and TLC. It was assumed to aminosugar by BioLC analysis and TLC staining.

• Microbiology and Biotechnology Letters
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• v.9 no.1
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• pp.29-34
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• 1981

To maximize the production of penicillin amidase from Estherichia coli (ATCC 9637), the media composition and several factors affecting the engyme production during fermentation were studied. The optimal media composition was found to be; 3.5% tryptone, 1.5% monosodium glutamate and 0.5% yeast extract. The addition of 0.15% phenylacetic acid as an enzyme inducer at the initial stage of cultivation increased the engyme productivity about 5 fold. It was found that the engyme activity reached maximum within 16hr of cultivation. The maximum production of the enzyme obtained was about 102.5 units/l broth under the optimized condition. The enzyme production was markedly increased by the optimization as compared with those previously reported.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1322-1329
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• 2011

Filamentous fungi colonizing rice straw were collected from 11 different sites in Korea and were identified based on characterization of their morphology and molecular properties. The fungi were divided into 25 species belonging to 16 genera, including 14 ascomycetes, one zygomycete, and one basidiomycete. Fungal cellulolytic and xylanolytic enzymes were assessed through a two-step process, wherein highly active cellulase- and/or hemicellulase-producing fungi were selected in a first screening step followed by a second step to isolate the best enzyme-producer. Twenty-five fungal species were first screened for the production of total cellulase (TC), endo-${\beta}$-1,4 glucanase (EG), and endo-${\beta}$-1,4 xylanase (XYL) using solid-state fermentation with rice straw as substrate. From this screening, six species, namely, Aspergillus niger KUC5183, A. ochraceus KUC5204, A. versicolor KUC5201, Mucor circinelloides KUC6014, Trichoderma harzianum 1 KUC5182, and an unknown basidiomycete species, KUC8721, were selected. These six species were then incubated in liquid Mandels' media containing cellulose, glucose, rice straw, or xylan as the sole carbon source and the activities of six different enzymes were measured. Enzyme production was highly influenced by media conditions and in some cases significantly increased. Through this screening process, Trichoderma harzianum 1 KUC5182 was selected as the best enzyme producer. Rice straw and xylan were good carbon sources for the screening of cellulolytic and xylanolytic enzymes.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.191-196
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• 2003

This study was carried out to investigate the isolation, identification, and antibacterial activity of lactic acid bacteria related to kimchi fermentation. Diluted kimchi soup was plated on the MRS agar media with CaCO$_3$ and incubated at $25^{\circ}C$ for 2 days. A total of 27 strains of lactic acid bacteria from various indigenous, spontaneously fermented vegetables (kimchi) were isolated. Combined methods of Bergey's manual of systematic bacteriology, BPB media analysis and 16S rDNA sequence analysis were applied for identification, however, their results did not coincide in several cases. Isolated lactic acid bacteria could be classified by the 16S rDNA sequence analysis as Leuconostoc mesenteriodes, Leu. carnosum, Lactobacillus curvatus, Lac. pentosus, Weisselia kimchi, W. cibaria, and Pediococcus pentosaceus. Leu. carnosum has not been reported in kimchi lactic acid bacteria. In addition, antibacterial activities of the isolates were tested with Bacillus subtilis, Escherichia coli, Salmonella enteritidis, S. paratyphica, S. typhi, Staphylococcus aureus, Shigella boydii, and S. sonnei. Some of isolates showed significant antibacterial activities to those pathogens.